Risk assessment for cardiovascular and respiratory mortality due to air pollution and synoptic meteorology in 10 Canadian cities
Health Canada, Environmental Health Science and Research Bureau, Population Studies Division, Ottawa, ON Canada K1A 0K9
Abstract Synoptic weather and ambient air quality synergistically influence human health. We report the relative risk of mortality and significance of air pollution effects on human health, controlling for weather type and season, in 10 major Canadian cities for 1981 through 1999. Mortality categories of all non-accidental, respiratory-, and cardiovascular-related deaths were assessed, and associated with the exposure of four air pollutants. We conducted this multi-city time-series study using Poisson generalized linear models within four seasons and six distinctive weather types. We report statistically significant relationships of mortality due to short-term exposure to carbon monoxide, nitrogen dioxide, sulphur dioxide, and ozone. There were significant modifications of risk with respect to the weather type, season, and mortality type, with respiratory-related causes significantly higher than that of cardiovascular death in 61% of the cases examined. Tropical-type weather in the spring and summer seasons pose the overall greatest risk due to air pollution exposure.